Previous designs to date have required considerable pretreatment, or have not allowed adequate aeration of the waste materials to promote rapid degradation, or have done so with exceedingly complex designs.
Fox, et al, U.S. Pat. No. 1,543,154 issued on 6-23-25, realize the need for pregrinding waste materials, but do so to a finely divided state. In addition, materials are suspended in water after grinding for conveyance to a large central tank, where solids and liquids are then separated. This design requires six months for the degradation of materials.
Komline, U.S. Pat. No. 3,054,663 issued on 9-18-62, uses a hollow drum with open ends, rotated on the longitudinal axis held horizontal, and employs axially extended vanes powered by cables, pulleys and electric motor to provide tumbling and agitation. While achieving the necessary aeration for rapid decomposition of waste organic materials, this design is very complex and separates materials into compartments.
Chester, U.S. Pat. No. 3,890,129 issued on 6-17-75, uses a wash drum rotated on the longitudinal axis, held horizontal. While providing a degree of agitation, this device does not allow sufficient aeration since it must be covered with a shroud on the sides and ends to prevent the composted material from falling out, and precipitation from getting in, thus leaching out nutrients. In addition, collection of the composted material is difficult in that it must be discharged through the mesh with the shroud removed while rotating.
Whiteside et al, U.S. Pat. No. 3,942,769 issued on Mar. 9, 1976 employ a drum rotated on the longitudinal axis, held horizontal, again allowing a degree of agitation of the waste materials to be composted. In this design, a door is provided in the cylinder wall to provide for insertion and removal of materials. However, this design also fails at providing the degree of aeration through the material to be composted which is essential to rapid decomposition.
Rotating a horizontal cylinder on the longitudinal axis provides some mixing of the composting material in that the material tends to flow by gravity when the angle of repose is exceeded. This agitation, however, is gentle and not conducive to thorough mixing of the composting material.
In addition to the above, tumbling (end-over-end) type milk churns are known.